### Problem/Motivation Convert drupalGet() $headers argument from indexed colon-separated strings or null values to an associative array format. This change was deprecated in drupal:11.1.0 and is removed in drupal:12.0.0. ### Proposed resolution Handled automatically by drupal-rector via the `DrupalGetHeadersAssocArrayRector` rule. ### How this rule was built This rule was produced with an AI-assisted workflow in which every step was verified manually by @bbrala. Its logic started from the matching drupal-digests entry, which was adapted to drupal-rector's conventions — a dedicated rule or an existing upstream rule configured into the Drupal 12 set — and covered with before/after test fixtures. Backward-compatibility was assessed and version-gated: safe rewrites are applied directly, while unsafe ones are wrapped via `DeprecationHelper` or moved to an opt-in breaking set. The rule was then live-tested against a set of contributed modules; where no contrib call site could be found, a static code sample was written in a test module to exercise it. A final automated QA pass covered type-guard, fixture coverage, BC-decision, registration and idempotency checks. ### References - Change record(s): [CR-3456178](https://www.drupal.org/node/3456178), [CR-3456233](https://www.drupal.org/node/3456233) - Related issue(s): [#3440169](https://www.drupal.org/i/3440169), [#3421105](https://www.drupal.org/i/3421105) ### Work items - Commit(s): [f58f6aaf7c](https://github.com/palantirnet/drupal-rector/commit/f58f6aaf7c9e) ### Credit - Implemented by: @bbrala - Reviewed / helped by: @mglaman --- *Filed retroactively as part of the Drupal 12 rector coverage effort. Closed as fixed; credit to be applied to the contributors listed above.* *AI was used extensively to build this rule and to file this issue. See [Dries Buytaert: AI-generated Rector rules for Drupal](https://dri.es/ai-generated-rector-rules-for-drupal) and [Björn Brala: Drupal Rector rules are config, not code. Mostly.](https://www.linkedin.com/pulse/drupal-rector-rules-config-code-mostly-bj%C3%B6rn-brala-vfpwe/).*